3 things to try:
1) Many people are apparently under the impression that cranking dynamic ram preview allocation to some huge value will make Vegas render faster or otherwise improve performance. This is not true- all it does is allow Vegas to cache more video frames in ram so that after a creating a dynamic ram preview you can play back a longer section of the timeline at the preview resolution without writing to file. Just because you CAN crank the value to 1.5 GB doesn’t mean you should, and unless you really need to change this to a big value, don’t. Default is 16.
2) Vegas 6 supports multithreaded rendering, both for writing to file and for building dynamic ram previews. If you have a dual, HT or multicore system, Vegas 6 will by default tax your processors much more heavily. If you have a reasonably small ram preview value specificed and still are having trouble rendering, in Options>preferences>video set max # of render threads to 1. This setting will make Vegas 6 tax your processors in a nearly identical manner to Vegas 5 (no multithreadded rendering in other words).
3) If Vegas 6 is hanging on you during editing (not rendering) you might try temporarily disabling the Media Manager and see if this helps stabilize Vegas 6- this component does eat up some system resources, and if you have tons and tons of files open in the library you may be pushing your system too hard.
Lastly, if you have a project that for sure renders on the same machine in Vegas 5 and does not in Vegas 6 after setting dyanmic ram preview to 16, max render threads to 1, media manager off, we’d like to get a copy of the .veg plus media. dr.dropoutATSYMbolsonypictures.com